From 59f02f19c796cdd83a9ec8751f83e10c42080a44 Mon Sep 17 00:00:00 2001
From: Jim Warner <james.warner@comcast.net>
Date: Tue, 18 Sep 2018 00:00:00 -0500
Subject: [PATCH] top: plug a minor hole in the vertical scrolling logic

In that commit referenced below, a few edge cases were
addressed regarding vertical positioning involving any
'hidden' tasks. But, 2 additional edge cases remained.

In a running top, if the user employed 'other filters'
(o/O) or 'user filters' (u/U) proper vertical position
was not ensured. And, while this could be easily fixed
by striking the home/end or up/down arrow keys, it was
very poor etiquette to shift this burden to the users.

So, this patch plugs that gap, automating the process.

Reference(s):
commit 9d59ddc4661453dc65a8fc81dd75bfea40b7696c

Signed-off-by: Jim Warner <james.warner@comcast.net>
---
 top/top.c | 11 ++++++++---
 top/top.h |  2 +-
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/top/top.c b/top/top.c
index 02c98ade..0cda7fa0 100644
--- a/top/top.c
+++ b/top/top.c
@@ -4231,7 +4231,8 @@ static void wins_stage_2 (void) {
    // fill in missing Fieldstab members and build each window's columnhdr
    zap_fieldstab();
 
-   // with preserved 'other filters', ensure a visible task on row #1
+   // with preserved 'other filters' & command line 'user filters',
+   // we must ensure that we always have a visible task on row one.
    mkVIZrow1(Curwin);
 
    // lastly, initialize a signal set used to throttle one troublesome signal
@@ -4943,7 +4944,10 @@ static void keys_task (int ch) {
       case 'O':
       case 'o':
       case kbd_CtrlO:
-         if (VIZCHKw(w)) other_filters(ch);
+         if (VIZCHKw(w)) {
+            other_filters(ch);
+            mkVIZrow1(w);
+         }
          break;
       case 'U':
       case 'u':
@@ -4952,6 +4956,7 @@ static void keys_task (int ch) {
             if (*str != kbd_ESC
             && (errmsg = user_certify(w, str, ch)))
                 show_msg(errmsg);
+            mkVIZrow1(w);
          }
          break;
       case 'V':
@@ -5780,7 +5785,7 @@ static const char *task_show (const WIN_t *q, struct pids_stack *p) {
          * In reality, this function is called:
          *   1) exclusively for the 'current' window
          *   2) immediately after interacting with the user
-         *   3) who struck 1 of these: up, down, pgup, pgdn, home or end
+         *   3) who struck: up, down, pgup, pgdn, home, end, 'o/O' or 'u/U'
          *   4) or upon the user switching from one window to another window */
 static void window_hlp (void) {
    WIN_t *w = Curwin;             // avoid gcc bloat with a local copy
diff --git a/top/top.h b/top/top.h
index 63ae678e..43fd9c25 100644
--- a/top/top.h
+++ b/top/top.h
@@ -390,7 +390,7 @@ typedef struct WIN_t {
 #endif
 
         // Support for a proper (visible) row #1 whenever Curwin changes
-        // ( or a certain vertical scrolling key has been struck )
+        // ( or a key which might affect vertical scrolling was struck )
 #define mkVIZrow1(q) { q->begtask -= 1; q->begnext = +1; }
 
         /* Special Section: end ------------------------------------------ */